We propose to work within the context of 2 NIH-funded grants at our institutions to define abnormalities in cardiac and pulmonary function that occur in infants as young children with Human Immunodeficiency Virus infection. The importance of HIV itself will be determined by comparing the study group of infants with HIV infection with control groups of seronegative infants from either seropositive mothers or high risk, seronegative mothers. We will determine the extent of cardiopulmonary dysfunction in symptomatic infants by more invasive studies, institute appropriate therapy. The 2 ongoing grants are the Bay Area Perinatal AIDS Center and the Northern California Pediatric AIDS Treatment Center. The first project documents the natural history of maternal-infant pairs in which the mother is either seropositive for HIV or is seronegative but in a high risk group, and will be the source of our control patients. Infants who subsequently develop HIV infection will be enrolled in the second project, the Pediatric AIDS Treatment Center. These infants, along with other infants in the Treatment Center diagnosed with HIV infection but who were not enrolled in the Perinatal Center, will be the source of our study group. They undergo intensive immunologic, infectious, psychometric and neurologic evaluations on a quarterly basis, and we will coordinate its studies with the existing follow-up schedules whenever possible, so that the patients are not required to make additional visits.